• Title/Summary/Keyword: Key Performance Index

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Power Allocation Scheme For Mobile Communication Systems Using Directional Transmission (방향성 전송을 사용하는 이동통신 시스템을 고려한 파워 할당 방안)

  • Lee, Woongsup;Jung, Bang Chul;Ban, Tae-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.11
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    • pp.2621-2627
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    • 2014
  • Directional transmission is one of key technology to solve the utmost problem that current mobile communication system faces, which is explosively increasing data traffic, since directional transmission can maximize the throughput of mobile communication systems. In this work, we consider power allocation scheme for mobile communication system which utilizing directional transmission. Especially, we consider the case in which multiple users in the same sector of base station, are served at the same time by utilizing directional transmission. For this scenarios, we consider equal power allocation scheme, Water-filling based scheme and inverse SNR scheme. Moreover, we propose beam power allocation scheme whose objective is to maximize overall system throughput by taking into account interference between different directional transmissions. Moreover, we have examined the spectral efficiency and Jain's fairness index of various power allocation schemes for directional transmission by using system level simulator that has been developed in our previous work. Through simulations, it has been verified that the proposed power allocation scheme can improve the spectral efficiency of the system by 28%.

Effects of Bar Deformation Height on Bond Degradation Subject to Cyclic loading (반복하중시 철근 마디높이에 따른 부착 손상특성)

  • Lee, Jae-Yuel;Kim, Byong-Kook;Hong, Gi-Suop;Choi, Oan-Chul
    • Journal of the Korea Concrete Institute
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    • v.15 no.1
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    • pp.17-24
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    • 2003
  • One of the reasons for brittle failure in reinforced concrete structures subjected to severe earthquake is due to large local bond-slippage of bars resulting in fast bond degradation between reinforcing bars and concrete. This study aims to evaluate effects of bar deformation height on bond performance, specially, bond degradation under cyclic loading. Bond test specimens were constructed with machined bars with high relative rib areas. The degree of confinement by transverse bars is also another key parameters in this bond test. From test results, amounts of energy dissipation are calculated and compared for each parameter. Test results show that bond strength and stiffness drops significantly as cycles increases. The confinement and high relative rib area are effective to delay bond degradation, as the reduction of bond strength of cyclic loading compared to monotonic loading decreased for bars with large confinement and high relative rib areas. The energy dissipation also increases as the degree of confinement and relative rib area increases. However, tested bars with very high rib areas show that the bond may be damaged at relatively small slip because of high stiffness. The study will help to understand the bond degradation mechanism due to bar deformation height under cyclic loading and be useful to develop new deformed bars with high relative rib areas.

A Test for Nonlinear Causality and Its Application to Money, Production and Prices (통화(通貨)·생산(生産)·물가(物價)의 비선형인과관계(非線型因果關係) 검정(檢定))

  • Baek, Ehung-gi
    • KDI Journal of Economic Policy
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    • v.13 no.4
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    • pp.117-140
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    • 1991
  • The purpose of this paper is primarily to introduce a nonparametric statistical tool developed by Baek and Brock to detect a unidirectional causal ordering between two economic variables and apply it to interesting macroeconomic relationships among money, production and prices. It can be applied to any other causal structure, for instance, defense spending and economic performance, stock market index and market interest rates etc. A key building block of the test for nonlinear Granger causality used in this paper is the correlation. The main emphasis is put on nonlinear causal structure rather than a linear one because the conventional F-test provides high power against the linear causal relationship. Based on asymptotic normality of our test statistic, the nonlinear causality test is finally derived. Size of the test is reported for some parameters. When it is applied to a money, production and prices model, some evidences of nonlinear causality are found by the corrected size of the test. For instance, nonlinear causal relationships between production and prices are demonstrated in both directions, however, these results were ignored by the conventional F-test. A similar results between money and prices are obtained at high lag variables.

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A study on the nation images of the big three exporting countries in East Asia shown in Wikipedia English-Edition (영어 위키피디아 페이지뷰를 통한 한중일 국가 인지도 비교)

  • Lee, Youngwhan;Chun, Heuiju;Sawng, Youngwha
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.5
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    • pp.1071-1085
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    • 2015
  • The researchers attempted to develop a way to extract a near real-time online nation image using social media. Referring to previous studies about nation images and the categories defined in Wikipedia, an ontology considering the characteristics of nation image was constructed. Separately, data sets from various social media were compared and the click view of Wikipedia English-edition was selected. The ontology was applied to the recent six years of the data extracted of the three big exporting countries of the east Asia, China, Japan, and Korea. To compare the nation images, correspondence analysis was employed to show images in the area of politics, society, culture, and economy. The nation images extracted are indeed the reasonable representation of them. The researchers verified them to a few known government policies and confirmed that it could be used to help government officers to make foreign policies to boost nation's export and to employ as a key performance index for them.

A Study on the Relation between IRI and PrI (평탄성 지수 IRI와 PrI의 상관관계에 관한 연구)

  • Kim, Kook-Han;Lee, Byung-Duck;Choi, Go-Il;Yang, Sung-Cheol
    • International Journal of Highway Engineering
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    • v.5 no.1 s.15
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    • pp.11-18
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    • 2003
  • Road roughness, as the key factor influencing not only drivers' ride quality and safety but also pavement deterioration, is one of the most important pavement performance indicator to be evaluated by users' subjective assessment. For this reason, a specific number of the pavement roughness has been adopted to monitor the condition of a road for pavement management systems and to evaluate the quality of newly constructed sections, however, none of the unified methodology was internationally accepted. In Korea highway network, road roughness has been used mainly to evaluate newly placed pavement by using 7.6m CP (California Profile meter) to calculate PrI (Profile Index). But this instrument is manually operated to measure road profiles by traffic closure and their interpretation depends on personal bias. Therefore, problems arisen from the manually operated instrument will be overcome by using the APL (Longitudinal Profile Analyzer) which can be operated in the speed of 80km per hour. A study was conducted to correlate the relation from both concrete and asphalt pavement between IRI (measured by APL) and PrI (measured by 7.6m CP). Test results showed that there was a good correlation between IRI and PrI.

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Evaluation of Dynamic Modulus based on Aged Asphalt Binder (아스팔트 바인더의 노화특성을 고려한 동탄성계수 평가)

  • Lee, Kwan-Ho;Cho, Kyung-Rae;Lee, Byung-Sik;Song, Yong-Seon
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.3
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    • pp.51-58
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    • 2008
  • Development of a new design guide which is based on empirical-mechanistic concept for pavement design is in action. It is called AASHTO 2002 Design Guide in USA and the KPRP(Korean Pavement Research Project) in Korea. The material characteristic of hot mix asphalt is a key role in the design guide. Therefore it is urgent to get a proper materials database, especially the dynamic modulus of hot mix asphalt. In this research, dynamic modulus test, which is based on aged asphalt binder, has been carried out and proposed the predicted equation of dynamic modulus. Nine different hot mix asphalt with three different asphalt binder have been used for the dynamic modulus test. Short-term aging, which is covers the time for the production of asphalt plant, transportation, lay-down, and compaction, can be simulated at $135^{\circ}C$ with 2 hour curing. Long-term aging has been carried out for a performance period of asphalt pavement. The dynamic modulus of asphalt pavement increases with aging time. As the nominal aggregate size increases, the change of dynamic modulus is not big.

A Study on the Time-lag Effects of Financial & Non-financial Performances of Balanced Scorecard (균형성과표의 재무적 및 비재무적 성과의 시차적 효과 특성에 관한 연구)

  • Jeong, Ki-Man
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.8
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    • pp.2103-2109
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    • 2009
  • Balanced Scorecard(BSC) is one of the ways to estimate the achievement results of enterprises which, beyond the simple financial index traditionally used for enterprise achievement result management system, aims to estimate and manage the key perspectives for the future and goal achievement of enterprises as financial perspectives, customer perspectives, internal business perspectives, learning and growth perspectives with a fully consistent and balanced measure, and moreover manage their relationships regarding cause and effect on its basis. Introduction of BSC can be a profound implication for management strategies not only in that its introduction itself has numerous direct effects but also in the way of understanding whether or not its sequential relations exist. Thus this study focused on if the introduction of BSC is effectual, and if there exist any time-lag sequential relations between the effects. The results of the this study indicate that the introduction of BSC has positive effects on the internal business perspectives, learning and growth perspectives, financial perspectives, with the last aspect lasting longer. After dividing perspectives of BSC into leading indicator and lagging indicator, the analysis on if there was some relationships between two indicators was done. As a result, the introduction makes internal process improve first, which has positive effects on financial performance next.

Analysis of the Optimal Window Size of Hampel Filter for Calibration of Real-time Water Level in Agricultural Reservoirs (농업용저수지의 실시간 수위 보정을 위한 Hampel Filter의 최적 Window Size 분석)

  • Joo, Dong-Hyuk;Na, Ra;Kim, Ha-Young;Choi, Gyu-Hoon;Kwon, Jae-Hwan;Yoo, Seung-Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.64 no.3
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    • pp.9-24
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    • 2022
  • Currently, a vast amount of hydrologic data is accumulated in real-time through automatic water level measuring instruments in agricultural reservoirs. At the same time, false and missing data points are also increasing. The applicability and reliability of quality control of hydrological data must be secured for efficient agricultural water management through calculation of water supply and disaster management. Considering the characteristics of irregularities in hydrological data caused by irrigation water usage and rainfall pattern, the Korea Rural Community Corporation is currently applying the Hampel filter as a water level data quality management method. This method uses window size as a key parameter, and if window size is large, distortion of data may occur and if window size is small, many outliers are not removed which reduces the reliability of the corrected data. Thus, selection of the optimal window size for individual reservoir is required. To ensure reliability, we compared and analyzed the RMSE (Root Mean Square Error) and NSE (Nash-Sutcliffe model efficiency coefficient) of the corrected data and the daily water level of the RIMS (Rural Infrastructure Management System) data, and the automatic outlier detection standards used by the Ministry of Environment. To select the optimal window size, we used the classification performance evaluation index of the error matrix and the rainfall data of the irrigation period, showing the optimal values at 3 h. The efficient reservoir automatic calibration technique can reduce manpower and time required for manual calibration, and is expected to improve the reliability of water level data and the value of water resources.

Effects of TR and Consumer Readiness on SST Usage Motivation, Attitude and Intention (기술 준비도와 소비자 준비도가 Self Service Technology 사용동기와 태도 및 사용의도에 미치는 영향)

  • Shim, Hyeon Sook;Han, Sang Lin
    • Asia Marketing Journal
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    • v.14 no.1
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    • pp.25-51
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    • 2012
  • Researches about the relationship between SST(Self Service Technology) and TRI(Technology Readiness Index) have been carried out after TRI was developed by Parasuraman and his colleagues(2000). We hypothesize Consumer Readiness can also influence consumer's motivation, attitude, and intent to use SST. Currently, there has been no research on this subject. In this study, we investigated the relationship between TR, Consumer Readiness and SST Core Attitudinal Model which Dabholkar & Bagozzi(1994) proposed. The researchers also investigated moderating effects of consumer traits and situational factors to verify the acceptance of such forms of service delivery by all kinds of consumers and under different situational contexts. Self consciousness, the need for interaction with an employee, and the technology anxiety were used as consumer trait variables. Perceived waiting time and perceived crowding were used as situational variables. 380 questionnaires were distributed to a sample group of people in their 20's and 30's, and the data were analyzed with structural equation model using AMOS 18.0 program. All of Cronbach's alpha values representing reliabilities were satisfactory. The values of Composite Reliability(CR) and Average Variance Extracted(AVE) also showed the above criteria, thus providing evidence of convergent validity. To confirm discriminant validity among the constructs, confirmatory factor analysis and correlations among all the variables were examined. The results were satisfactory. The results of this study are summarized as follows. 1. Optimism and innovativeness of TR partially influenced the motivation to use SST. People who tend to be optimistic use SST because of ease of use and fun. The innovative however, usually use SST due to its performance. However, consumer readiness of role clarity, ability and self-efficacy influence all the components of motivation to use SST, ease of use, performance and fun. The relative effect of consumer readiness on the motivation to use SST was much stronger and more significant than that of TR. No other previous studies have examined the effects of Consumer Readiness on SST usage motivation, attitude and intention. It is academically meaningful that the researchers verified that Consumer Readiness is the important precedent construct influencing the self service technology core Attitudinal Model. Our findings suggest that marketers should consider fun and ease of use attributes to promote the use of self service technology. In addition, the SST usage frequency will rise rapidly when role clarity, ability, and self-efficacy which anybody can easily handle SST is assured. If the SST usage rate is increased, waiting times for customers could be decreased. Shorter waiting time could lead to higher customer satisfaction. It may also result in making a long-term profit owing to the reduced number of employees. Thus, presentation of using SST by employees or videos showing how to use it will promote the usage attitude and intent. 2. In SST core attitudinal model, performance and fun factors among SST usage motivation affected attitudes of using SST. The attitude of using SST highly influenced intent to use SST. This result is consistent with previous researches that dealt with the relationship between motivation, attitude and intention. Expectation of using SST could result in good performance just like the effect of ordering menu to service employees and to have fun since fun during its use could promote more SST usage rate. 3. In the relationship among motivation, attitude and intent in SST core attitudinal model, the moderating effect of consumer traits(self-consciousness, need for interaction with service employees and technology anxiety) and situational factors(perceived crowding and perceived waiting time) were tested. The results also supported the hypothesized moderating effects except perceived crowding. The highly self-conscious tended to form attitudes to use SST because of its fun compared to those who were less self-conscious because of its performance. People who had a high need for interaction with service employees tended to use SST for its performance. This result indicates that if ordering results are assured, SST is easily accessible to even consumers who have a high need for interaction with a service employee. When SST is easy to use, attitudes strengthen intent among people who had a high level of anxiety of technology. People who had low technology anxiety formed attitudes to use SST because of its performance. Service firms must ensure their self service technology is designed to be easy to use for those who have a high level of technology anxiety. Shorter perceived waiting times strengthened the attitude to use self service technology because of its fun. If the fun aspect is assured, people willing to use self service technology even perceive waiting time to be shorter than it actually is. Greater perceived waiting times form higher level of intent to use self service technology than those of shorter perceived waiting times. This implies that people view self service technology as a faster alternative to ordering service employees. The fun aspect of self service technology will attract a higher rate of usage for self service technology. 4. It has been proven that ease of use, performance and fun aspects are very important factors in motivation to form attitudes and intent to use self service technology regardless of the amount of perceived waiting time, self-consciousness, need for interaction with service employees, and technology anxiety. Service firms must consider these motivation aspects(ease of use, performance and fun)strongly in their promotion to use self service technology. Ease of use, assuring absolute performance compared to interaction with service employees', and adding a fun aspect will positively strengthen consumers' attitudes and intent to use self service technology. Summarizing the moderating effects, fun is the most valuable factor triggering SST usage attitude and intention. Therefore, designing self service technology to be fun will be the key to its success. This study focused on the touch screen self service technology in fast food restaurant. Although it has its limits due to the fact that it is hard to generalize the results to any other self service technology, the conceptual framework of this study can be applied to future research of any other service site.

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Innovation Technology Development & Commercialization Promotion of R&D Performance to Domestic Renewable Energy (신재생에너지 기술혁신 개발과 R&D성과 사업화 촉진 방안)

  • Lee, Yong-Seok;Rho, Do-Hwan
    • Journal of Korea Technology Innovation Society
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    • v.12 no.4
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    • pp.788-818
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    • 2009
  • Renewable energy refers to solar energy, biomass energy, hydrogen energy, wind power, fuel cell, coal liquefaction and vaporization, marine energy, waste energy, and liquidity fuel made out of byproduct of geothermal heat, hydrogen and coal; it excludes energy based on coal, oil, nuclear energy and natural gas. Developed countries have recognized the importance of these energies and thus have set the mid to long term plans to develop and commercialize the technology and supported them with drastic political and financial measures. Considering the growing recognition to the field, it is necessary to analysis up-to-now achievement of the government's related projects, in the standards of type of renewable energy, management of sectional goals, and its commercialization. Korean government is chiefly following suit the USA and British policies of developing and distributing renewable energy. However, unlike Japan which is in the lead role in solar rays industry, it still lacks in state-directed support, participation of enterprises and social recognition. The research regarding renewable energy has mainly examinedthe state of supply of each technology and suitability of specific region for applying the technology. The evaluation shows that the research has been focused on supply and demand of renewable as well as general energy and solution for the enhancement of supply capacity in certain area. However, in-depth study for commercialization and the increase of capacity in industry followed by development of the technology is still inadequate. 'Cost-benefit model for each energy source' is used in analysis of technology development of renewable energy and quantitative and macro economical effects of its commercialization in order to foresee following expand in related industries and increase in added value. First, Investment on the renewable energy technology development is in direct proportion both to the product and growth, but product shows slightly higher index under the same amount of R&D investment than growth. It indicates that advance in technology greatly influences the final product, the energy growth. Moreover, while R&D investment on renewable energy product as well as the government funds included in the investment have proportionate influence on the renewable energy growth, private investment in the total amount invested has reciprocal influence. This statistic shows that research and development is mainly driven by government funds rather than private investment. Finally, while R&D investment on renewable energy growth affects proportionately, government funds and private investment shows no direct relations, which indicates that the effects of research and development on renewable energy do not affect government funds or private investment. All of the results signify that although it is important to have government policy in technology development and commercialization, private investment and active participation of enterprises are the key to the success in the industry.

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